FIG 4.

Identification of N-terminal residues of P critical for RSV polymerase activity. (A) Polymerase activity assays in the presence of P mutants. BSRT7/5 cells were transfected with plasmids encoding the wild-type (WT) N, M2-1, and L proteins, the pMT/Luc minigenome, and WT or mutant P proteins, together with pCMV-βGal for transfection standardization. Viral RNA synthesis was quantified by measuring the Luc activity after cell lysis 24 h after transfection. Each luciferase minigenome activity value was normalized based on β-galactosidase expression and is the average of results from three independent experiments performed in triplicate. Error bars represent standard deviations calculated based on three independent experiments made in triplicate. (B) Western blot analysis showing efficient expression of P mutant (E2A to G10A and F20A to G26A) proteins in BSRT7/5 cells.